Reversible slide film feed



April 1950 J. A. VAN DEN BROEK 2,505,016

' REVERSIBLE SLIDE FILM FEED Filed March 6, 1947 gvwmvbom JA/v A .-VA/v DEN BR EK Patented Apr. 25, 1950 UNlEEED eerie-E 2 ;50 5, 016 '-REVERSIBLECSLIDEFIEMFEED vnJanA s l'ianideniBroekaAnn Arbcr Mich iassignor i gug lncorpqrated, Ann Arbor, Mich., a corporation of, Michigan Application March- 6, 1947;serial Noz-"732g794 -8' Qlai;ms. (01. 88 13,

This invention relateslto means for'fifeeding a strip :.of film bearing :pictures or other data through a; projectionaorli like apparatus and v is more; particularly concerne'dvwwith .such mechanism wherein. a reversible. slide .feedisv employed for moving the film s incleither zzdirection at thewilldof 31711900136122.1301, :tcorrelated' with :a suitable arrangement for holdingertheifilm flat at the :projection;apertureyduring projection; andhreleasing it: for movementduring the feed operation.

Slides feeds avfor-l picture strips correlated with means-tor.openingta'filmtgate'when .the film is to be:advanced havevbeen heretofore provided, but

toimy'-kn0w1edge:n0ne. -f .these impractical use re. .capable of,-;r.eversing.:movement :of the film While retaining vsynchronous association with the pressureiplate-s'uoperating' means. .present invention embodies a distinct and useful advantage-zoverxsuch apparatusinthat, ,for. example; a lecturer; usingsajlantern containinglmy novel slide film apparatus "ma irreyerserthe; feed ofxthefilm htiah'yfiimc in nrdenjtotgo back-:to. a picture for reference purposes.

, lt is a major object/pf my. invention-therefore to provide a noveliireversible "film slide feed mechanism'correlated with meansvforsholding. the film at: aproj-ectionor likea'aperturewhichlis released synchrononsly and: automatically to :permin-movement Qfzithe; filmziin; eitherzsdirection.

,Other objects gofgdzhej invention will; presently appear as the.idescription-proceeds in, connection with the+appended,claimsand the annexed, drawines wh ein: a s

Figure 1 is a diagrammaticgwiew in side eleva- -In afi m-ezs lde' teedzme han m, ac ordin toapreferredembodimentof the; invention, which is, reversible .as indicated-bygthe full and 1 dotted line of thefilm contacting vpawl-in the drawing, and is .operably econnected ,,to 1 a pressure plate operating mechanism ,for, releasing the film: to

permit. .feed movements;

,5 Figure 2v isa; side elevation, similar: to Figure 1, illustrating the position of the parts at the bottom, of. the-.feeds-bstrokev when; the film is: fed

in the direction, of .the full linearrow; and; with g the pressureplate. 0128116120 permit 7 suchmovementaprior towspring returnof the parts tozthe position of 'Figure lgand Figure 3. isan enlarged fragmentary iew illusratin the film. e asi egp structure.

Injthe illustramd: BmbQdiment of; my invention the filml I Which preferablyhas a serieshof the henebf if dthmusvhsanlmreat thatcomprises alminsqtifiaizg las .nlates slllflnd .lsfintrposed in them-projection light path of aaconventional projectonhavingcthe:usualscondenser lenszassembly .4 indicated .at l i l forgsupplying light to the film gate an cl:.anobjective .lenstassemblyuindicated at! Elfor projecting .the'imageon a suitable screen.

Plate r1 2. is rigidlysmountedsin the apparatus with ,its .flat inner-t face tparallel .tosthe direction oflmoticmefcthefilm. A Hates-ti issimilar incconstructionzto plate l 2; ,hut:. issrockablylmounted at iSnonilthequpperlend;:oiaasleven ":Whibh; iswspivoted tatl. itslloarergendc at; l8 :uponca suitable,v stationarylpart; :l tssof the. projector. Thespurposelof pivot I8 is to permit lever l-luto; rock. plate =13 orting; flat; ,guide wall in .thebody of the prc t r, an have en ar ed: slide plate retainer ,1 heads; at their center ends, as illustrated infFigures 14and2 o. ha he p o id ir-gui e n :re ai amountin ;io z nabl ha p e. to slide 1939K: ands. rthri t sd r tie para l t desired ect q s'h nm mentuof the 11 and parallel to the inneryflatiace 10f plate,;,|,2. h eh a-. :sed; head d-1 outer sen of th studs ta r la 2 imposi q p ciector. pm a-wlyi iiat u .o a mn r11 kwa lof' r iecto woye w whic ha idesw r ca l vand-1n Which @studs Z6 and 27 are; rigidly mounted. -,A suitablecoilcd tension Ispri ze is connectedgto ri i arm 4-2 Qfk plate; ztaatsene; end: and; anchored to a,zstationary;part .3I of the -projector, whereby springzfiwco stahtl ur e 1a 1 p- Ward toward its position illustratedinrFigure 1, excess =upward movement ;;-.being prevented aby studs c-26;a,nd=21.

- 0n thesside .toWa Ids;.,the film,-;plate 2 31s -progvidedgwith; an pml'ectionqtizlqn which a lever- 33 is pivoteds satfi, -Aleai smihg=35eanchoredatits lower end at 36 to plate 23 and bearing against a. pin 31 rigid with lever 33, constantly urges lever 3o counterclockwise toward film ll.

At the upper end of lever 33, a reversible toothed pawl 38 is plvotally mounted on pin 39. Pawl 38 comprises two oppositely directed sharp teeth 48 and 41, either adapted to engage the sprocket holes in the film depending upon the direction of movement desired. Teeth 48 and Al are preferably sharp for entering the sprocket holes in the film, and the pawl 38 is preferably formed with a straight camming surface 42 which is common to both teeth and is adapted to ride on the film surface during the non-feeding stroke of the slide 39 with stop faces 42 and 43, and a tension spring 44 is eccentrically connected to pawl 38 at one end and anchored on lever 33 at the other end. A fixed stop 45 is provided on lever 33 adapted to be engaged by face 43 of pawl 38 when the pawl isinthe full line positionof Figure 3, and by face 4210f pawl 38 when the pawl is in the dotted line position ;of Figure 3. Spring 44 urges the pawl agaln'st the stop in either of these two positions.

Plate 23 is provided on the edge adjacent the film with'a generally vertical cam comprising a straight low face 46, a straight high face 41, and a, short inclined face 48 interconnecting them. This cam is adapted to be engaged by a free roller 49 idly rotatably mounted on the end of an arm 5-! rigid with lever l1, whereby roller 49 is resiliently urged by spring 2| into engagement with the cam on the slide plate 23.

When slide plate 23 is moved downwardly from itsfupper limit position illustrated in Figure l, where roller 49 is riding in the low face of the cam and the film gate is closed, to the lower limit position of Figure 2, roller 49 climbs face 48 to the high face 41 of the cam and thus causes lever I? to rock counterclockwise. This accomplishes opening of the film gate.

Figure 1 illustrates the parts after a film has been threaded through the mechanism and just before it is desired to move it one frame downtwo sprocket holes 59, preferably near the uppermost of these two sprocket holes, when the parts are in the positionof Figure 1 as illustrated. At this time roller 49 is disposed on face 48. Film feed is accomplished by pushing down on tab 29, or an'extension-thereof extending through a suitable slot in the exterior wall of the projector, against thetension of the spring 28. Tooth 48 slides downwardly along the surface of the film and enters the first sprocket hole 58 that it encounters since the lever- 33 is resiliently urged against the film by spring 35. Further downward movement of plate 23 will result in corresponding downward movement of the film. The torque exerted on pawl 38 by resistance of the film is opposed by engagement 'of the pawl with stop 49 so'that pawl 38 remains in the full line position. Also the torque exerted by the film moving operation on lever 33 is less than the strength of spring 35, so that pawl 38 remains pressed against the film during the film feed stroke.

Duringthe period that tooth 49 is sliding on the film, the film remains stationary but is released from gripping engagement by plates l2 and I 3. This is accomplished by the camming action of face 48 quickly acting through roller 49 to rock lever l1 counterclockwise to the position of Figure 2, thereby separating plates l2 and 13 before tooth 48 enters a sprocket hole and the film starts to move. This separated position of plates 12 and i3 is maintained during the entire down stroke of plate 23, by roller 49 riding the high face 41, as illustrated in Figure 2.

" After plate 23 has reached its downward limit of stroke and is in the position illustrated in Figure 2, the operator releases the tab 29 and this permits spring 28 to return plate 23 upward to the position of Figure 1. During this return, the tooth 48 disengages itself from the sprocket holes of the film and the cam face 42 merely rides on the film surface without moving the film. During upward travel of plate 23, the film gate remains open all the while that roller 49 remains on face 47, but as soon as roller 49 descends face 48 to low face 46, which takes place at the conclusion of the return stroke of plate 23, lever l! is permitted to rock clockwise under influence of spring 2| to thereby close the film gate and grip the film frictionally to hold it flat between platesl2 and I3 during projection. The parts are now again in'the position of Figure 1 and ready for a new feed'operation.

The above described operation takes place when it is desired to move a film from top to bottom in Figures 1 and 2. When it is desired to move the film in the opposite direction, it is necessaryonly to turn pawl 38 clockwise about 90 on its pivot from the full line position of Figures 1-3 to thedotted line position illustrated therein, wherein face 42 engagesthe stop 45 and the tooth 4| becomes engaged with the surface of the film. It will be seen that spring always maintains the *pawl pressed against the film.

I operation, when the pawl is in the dotted line positionof Figures 13, on the down stroke of plate 23, cam surface 42'simply rides over the film without feeding the film as it did during the upstroke when the film was fed in the opposite. direction. Thus during the entire down stroke of plate 23,-there is no film feed although when the roller 49 is cammed up onto face 41 plate I3 is rocked out of engagement with the film and maintained there. When the tab 29 is released after completion of the down stroke, spring 28 pulls plate 23 up toward the position of Figure 1 and since pawl 38 is held against rotation by stop 45 it is on this up stroke that the film feed takes place in this condition of operationof the apparatus. I

During thetime that the film is being moved upwardly, roller-494s riding on face 47 so that the plates l2 and' I3 remain in the position of Figure 2 and the parts are so arranged and dimensioned that completion of. the spring .urged upward stroke is effected as near as possible to the time that roller 49 descends face 48 so that there will be noappreciable feed stroke of the film afterthe pressure plates clamp the film.

I' have thus provideda reversible slide film feed which automatically opens the pressure plate whenever the film is beingmoved and closes it when a feed movement is accomplished in either direction of film movement.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to. be considered in all respects. as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. In a strip film handling apparatus, releasable means for holding a film against longitudinal movement, reciprocable film feed means reversible for selectively feeding said film in one direction or the other comprising a film feed member reciprocable longitudinally of the film operatively engaged with the film during feed stroke movement in the desired direction and inoperable to feed the film during its non-feed stroke and means for reversing said operative engagement of said member with the film to select the direction of film feed, and means comprising coasting means on said film feeding means and said releasable means for automatically releasing said releasable means during said feed stroke in either direction of film feed and for holding the film against longitudinal movement during said non-feed stroke in either direction.

2. In a film handlin apparatus, a releasable film gate member adapted to hold a film stationary, a reciprocable member having a first part for operably engaging and feeding the film in one direction during a reciprocation cycle and a second part for operably engaging and feeding the film in the opposite direction during a reciprocation cycle, means for moving one or the other of said parts into operative engagement with said film for selecting the direction of film feed, and cooperating means on said film gate member and operated by the reciprocable member for opening the film gate to release the film during the period that the film is being fed regardless of the direction of feed of the film.

3. In a film handling apparatus, a film gate, means for holding the film against longitudinal movement at the film gate, a slidable member, a pawl on said slidable member adapted to engage the film for moving it in one direction durin reciprocation of said member, means for reversing the pawl so as to feed the film in the other direction during reciprocation of said member, and means on said slidable member operably connected to said film holding means operative to effect opening of the film gate during said movement of the film in either direction.

4. The film handling apparatus defined in claim 3, wherein said film holding means comprises a pair of parallel transparent plates, one of which is stationary and the other of which is resiliently urged toward the first.

5. The film handling apparatus defined in claim 3, wherein said pawl is pivoted on said member and means is provided on said slidable member for locating said pawl in said reversed positions.

6. In the film handling apparatus defined in claim 3, said film feeding means comprising a 5 member slidably mounted for reciprocation parallel to the direction of film feed, manual means for moving said member in one direction and resilient means for returning it, and cam means on said member operably connected to said film holding means.

7. In the film handling apparatus defined in claim 3, said film holding means comprising a pair of parallel plates, one of which is stationary and the other movable, a pivoted lever for mounting said other plate, spring-urged means to bring said plates together, and a cam operated by said film feeding means operably connected to said lever.

B. In a strip film handling apparatus, releasable means for holding a film against longitudinal movement, reciprocable film feed means reversible for selectively feeding said film in one direction or the other comprising a film feed member reciprocable longitudinally of the film 5 operatively engaged with the film during feed stroke movement in the desired direction and inoperable to feed the film during its non-feed stroke and means for reversing said operative engagement of said member with the film to select the direction of film feed, and means comprising cam means on said reciprocable feed member and an associated cam follower connected to said film holding means for automatically releasing said releasable means during said feed stroke in either direction of film feed and for holding the film against longitudinal movement during said non-feed stroke in either direction.

JAN A. VAN DEN BROEK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

